Cable sheathing



m L mm 1 RN. H 3, m mm M m w a m w mm m 2 W 7 /5. a m E s w 3 w \\\\u (nJ. E. MGLAUGHLIN CABLE Sl-IEATHING Ju ly 7, 1953 Flled Jan 8, 1949 July7, 1953 J. E. MGLAUGHLIN CABLE SHEATHING 3 Sheath-Sheet 3 Filed Jan. 8,1949 urlllIl/f/ll/ l VIIIIIII// IN VEN TOR. JOSEPH E. MC LAUGHLIN /M WWPatented July 7, 1953 vii-N TED f STATES PATENT orserce i f 1 2,644,353t Q CABLE "SHEATHING Joseph ELMc'Laug-hlin, Pottsville, Pa, assignorstnCompany of America, :Pittsburgh,

Pa,, a corporation of Pennsylvania Application ifanu'ary s, 194aiseria1N .eases (c1. so-4) .2 Claims.

"This invention relates in "general 'to the fabri ample of the inventionis its adaptation to the manufacture'pf aluminum or aluminum alloysheathed, *papcr "insulated telephone cable as a substitute forpresently employed lead sheathed telephonecable- Numerous attempts havebeen made -to substitute-other metals and alloys for the lead and leadalloys insheathedeaibles. The lead'orlead alloy, sheathed cables areproduced by extruding the metal sheathing directly onto the cable to besheathed. "This practice has been considered satisfactory because of theiact that the lead, and numerous al-loys "thereof, such as lead alloyscontaining antimony, calcium-and other alloying elements, singly and in-'conihination, can be extruded at temperatures below the temperaturesat which normally employed insulation would be damaged as by charting.

The present invention is di-recte'd to equipment which eliminates thenecessity of employing extru'sion 01* melting temperatures inthesheathing metal -'or alloy, and the invent'ion may -be termed a-c'0li:l working process in that no external *heat is requiredfnor doesthe sheathing material reach a temperature, during its working andapplic'ae ti'on to an insulated caldle,thatis in juriou's to thec'atile-orits insulation.

at is'an object of the invention to provide anapparatus for sheathingcahle in relatively long lengths Without high temperature in juryto"-the cable and/erits-insulation. v

*It is another -:object or the invention to provide an apparatus for*the continuous production o'f metallically sheathed, insulatedcahle.

'-Other objects and advantages will present themselves :to those skilled"in this art following consideration *of the specification and drawings,intvhieni I Fig. '1 represents 1amechanisminside-elevation suitable "forreducing :and 'siriliingtubular 's'h'e'athmg on cable;

Fig. '2 represents a fragmentary sectional ele vation, to enlargedscale, thr'oug'h the reducing head or millof'themechanism of Fig.1;

' Fig. 3 represents a fragmentary sectional elevation, to enlargedscale, through the sinking dies of the mechanism 'ofFigJl;

Fig. 4 represents :an alternative'mechanism in plan .view suitablefor-reducing andsink ingtiibw lar sheathing on cable; "Fig. 5 representsa fragmenta'ry sectional'e'levation, to enlarged sca'le, through thepositive feeding and reducing instrumentalities of the mechanism-ofFigri I V 1 Fig. 6 represents a f-ragmentary sectional :elev-a'tion, toenlarged :scale, through a portion oil the left-hand end :of themechanism of Fig. r4;

-Fig. '-7 represents a fragmentary end elevational view taken in thedirection 'o'f the arrows 7- 1 on Fig. 5:;

"Fi 8 represents a sectional elevation taken Fig. 9 represents afragmentaryrend elevational tubular bloomsaand-ztheimterior cable thatwould cause .fthecabl'e totwi'st on itself or becomeskinked within thebloom. i lhebloom is reduced-in wall thickness andcins'ide diameter withattendant. increase in length. illhesreduction'step may be continuous.or .-intermittent,y.and the reduced bloom, together:Wil'ih:itSJIGOSGIMSuDDQItGdl'intel iQr cable, .is thereaftersubjecteditoga-tleastzoneisink ing operation to :bring the ireduceid.bloom' or tubular sheath :dow-n into Etighb :conforr'ning contact withthe. interiorrcable. :No appreciablezre'lative z-movement, rotational,"OI linea1, should exist between the reduced tubular -:sheathing :and:interior cable :during the fihetl sinking operation which ;p'laces,,the':sheathing in tightclamping; contact on the :cable. Otherwise, :thecableand/or its @insulati'on :would be exposed to elong-aei tion,rbreakage or partial breakage, which "would interfere with orinterrupt,the-continuitycf :the electrical circuit through thevfinished product.

The drawings --i-llustrate'=suitablezapparatm .;for, practicing theinvention. In Figs. .l through 3 a vrotary ball type ,reducingcnill i0is arranged .in

tandem with one or 1110138 sinking dies 12 and power-driven bull block.UL. The .rotary balllref.

ducing mill II'U includes .one or moreiball. support: ing dies to.rotataloly mounted 'in .a stationary housinglfi, the'die or dies I16Tbeing ,poweredr'ivenj by means of asu'italole electric motor 20,.g'e'a'ri connected through motor pinion-Z I "and gear-22, formed 'orotherwise attached to the exteriorperiphery of'each'dielt." y

The sinking dies l2 are preferably secured in axial alignment with thedischarge throat 24 of the rotary reducing mill l0, replaceable dieelements or inserts 25 being supported within each sinking die 12.Several sinking die inserts may be supported within a single housing, asdistinguished from the one or more separate sinking dies [2. In eithercase, the die inserts 25 are preferably vertically movable within guides21 to permit axial alignment and direct pull on the sheathed cableduring build-up of the same on the bull block M.

A tubular or hollow mandrel rod 26, having an enlarged tubular mandrelnose or tip 29 formed integral or otherwise attached thereto, is securedat its rear end within a stationary clamp member 28 and extendsforwardly through a seamless tubular bloom 30 into position within therotary .ball die or dies I6, where the mandrel tip 29 cooperatestherewith to control the interior diameter of the reduced tubularsheathing member 3|.discharged from the rotary ball re ducing mill l0.Cable 32 to be sheathed is supplied from any suitable source, such as afree running reel 33, and is loosely supported within the hollow mandrelrod 26, mandrel tip 29 and reduced tubular sheathing member 3|, thereduced sheathing and cable being suitably connected or attached attheir forward ends to provide simultaneous advance of the reducedsheathing 3| and cable 32 through the rotary ball reducing. mill 10.

The initial sheathing material or bloom 30 is positively urged or fed tothe right, as viewed in Fig. 1, by means of a pusher head 34, which mayengage the end of the bloom 30 or clamp on the exterior surface of thesame. The pusher head 34' is axially translated through the medium of apower-driven lead screw 35.

In the preferred practice of the invention, with the equipment thus fardescribed, the following operating steps are performed; (1) the tubular,thick-walled bloom 30 is positioned with its forward or leading endadjacent the reducing mill (2) the tubular mandrel rod 26, and itsattached mandrel tip 29, are introduced through the pusher head 34 andbloom 3|]; (3) the mandrel rod 26 and bloom 30 are advanced to positionthe forward'end of the bloom and the" mandrel nose or. tip 29 incooperative relationship within the rotary ball die or dies l6, in whichposition the opposite end orrearward portion of the mandrel rod 26 isclamped against axial or rotational movement in the clamp 28, and thepusher head 34 is brought into position to engage the rear end of thebloom 39;"(4) the cable 32 to be sheathed is threaded through themandrel rod 26 and mandrel tip 29 to provide a short length, say twofeet, of the same in advance of the reducing mill l0; the mill l0 andpusher head 34 are actuated to provide a short'length, say one foot,fofreduced tubular sheathing 3|, after which the 'mill and pusher head areinterrupted and the forward end of cable 32 positively attached to theforward reduced end of the tubular sheathing 3|; (6) the mill I0 andpusher head 34 are again actuated to provide an additional length ofreduced sheathing 3| in suffici ent length to reach the bull block l4,after which the mill and pusher head are again interrupted; (7) asufficient length of the discharged,

reduced sheathing 3|, with its interior cable 32 loosely supportedtherein, is swaged down and pointed, in any well known swagingmechanism,

and the forward end thereof threaded through the sinking dies I2, wherepositive attachment is made to the bull block l4; (8) the bull block I4,mill l0 and pusher head 34 are power actuated in proper timedrelationship to perform uninterrupted reduction on the bloom 30 andsinking of the reduced and elongated tubular sheathing 3| on theinterior cable 32.

It will be understood that simultaneous operation of the pusher head 34,reducing mill l0 and bull block M will perform an initial bloom reducingoperation followed by a final sinking operation of the reduced tubularsheathing material 3| onto the interior cable 32. The power drives forthe feed screw 35, reducing mill l0 and bull block l4 are properlycoordinated to provide a continuous process for the production of asheathed cable. It is also to be observed and understood that the bloom30, its reduced tubular extension 3| and the interior cable 32, althoughentirely devoid of relative rotational movement, are subjected torelative axial movement through the reducing die or dies 5 and sinkingdies l2, exclusive of the sinking die l2 adjacent or closest to the bullblock M. The last-mentioned sinking die l2 performs the actual physicalclamping of the tubular sheathing entering this die onto the cable 32and hence there can be no appreciable relative movement between thesheathing and cable within the die during this final sinking operation.It should be understood that the final die sinking operation may producea slight elongation of the outer skin or surface of the external tubularsheathing. It is significant, however, that there be no relative axialmovement between the interior cable and surrounding sheath in theimmediate vicinity of the interior surface of the sheathing that isbrought into clamping contact with the cable or its insulation. Anysinking performed by the preceding dies |2 merely serves to reduce thesheathing with attendant elongation of the same without causing physicalclamping contact on the interior cable.

The operation of the sheathing equipment thus far described is devoid orfree from relative rotational movement between the sheathing materialand interior cable. The operation of the equipment is likewise devoidand free from appreciable relative axial movement between the cable andsheathing material in the final sinking die, particularly in the zonedefined by the interior surface of the tubular sheath in clampingcontactwith the interior cable. Otherwise, relative axial movement between theinterior cable and its exterior sheathing during the final sinking passwould react to set up tensile forces that would be susceptible ofrupturing the cable and/or its insulation.

On reference to Figs. 4 through 10 a modified or alternative form ofcable sheathing apparatus is illustrated. In this form of apparatus theactual reducing step is performed in an intermittent bloom reducer ofthe general, type described in United States Patent 1,810,886 to GeorgeE. Neubert, patented June 16, 1931. Except for the substitution of anintermittent bloom reducer, the net result of the operation of thealternative equipment of the invention is similar to that presupportedupon a base casting d through the medium of suitable keyconnections 42The saddle 30 is power reciprocated on the bas 40 through the medium ofa niotor driven crank 44 and connecting rod 45 interconnecting the crankand saddle.

Sector shaped swaging or "reducing rnember's 4B are supported within thesaddle 39 and coo erate to for'm'a reduction pass for a tubular bloom 48positively 'fed thereto. The swaging -'elements 46 are secured onoscilla'tably journal-led shafts 50, the outboard ends of which carrygear sectors 52 secured thereto in engagement with racks 53 rigidlysecured to the main base' c'as'ti n'g 40. It

will be observed that reciprocation of saddle member 39 will result inpositive rocking oscillation of swaging elements 46. The-main casting 40is provided with an extending frame '54 which serve to support a tubularmandrel rod 55, man drel rod clamping head 55 a'ndmandrel rod indexinghead 58. The mandrel rod 55 is provided with an integral or positivelyattached ta ered tubular nose section 50, and-extends rearwardly whereit is releas'aloly clamped "against axial movement by means of a hingedmandrel rod engaging latch '52 supported on the clamp 55. immediately infront of the clamp 56 is the mandrel rod indexing head 58. This head, inits simplest form, comprises a crank member secured to the exteriorsurface of the mandrel rod, as by The crankis a, threaded clamping screw64.

6 in a continuous sinking operation. bloom redu'c'er 3 6 o erates in amanner to intermittently and positively feed the starting bloom 4 8 inre1a tively small increments into position to be reduced downwardly andforwardly (to the right as viewed in Figs. 4 and 5) along the taperednose to of the tubular mandrel rod 55 by means of f'orw-ardreciprocation or the saddle 39 and its su ported tube swagi ng elements4'6. 7

In the practice of the invention with the e uipment illustrated in Figs.4 through lo, the relatively thick-"walled bloom '48 is fed overthetubular mandrel rod 5 and projected through the clamping chucks M and i5intoposition to be reduced by the swaging elements 46in coop: orationwith'th'e tapered mandrel nose-50. Forward reciprocation or the saddleand its sup ported swagers t'd,-serves to reduce the bloom to elongatethe same forwardly beyond the end oi the tapered nose 60.

attached throughth'e medium of a connecting rod '65 and universalcoupling 68 to one arm of a bell crank 68 pivotally secured to a bracket10 attached to the framework 54. If desired, the indexing head 58 may beclamped on the tubular bloom 48 and perform its prescribed function, ashereinafter described.

A positive bloom feeding device is located adjacent the saddle 30. Thisfeeding device comprises a box-like frame or housing 12 secured to theframe 30. 'Slidable within the housing 12 is a channel shaped housingmember 73 in which, are mounted upper and lower bloom engaging chucks "Mand i5, respectively. The channel shaped housing 73 is provided withupwardly extending lugs or ears 16 which project through an aperture l!in the top wall of housing '12. Th lugs 76 serve to support a pivot pin18 upon which is oscillatably mounted in link 80. having a cam surface82 eccentric to the pivot pin 73-.

The housing 72 is equipped 'withbrackets' or integrally formed spacedlugs 83 vbetween which an actuating yoke '35 is pivotally supported uponpivot pins 86. The yoke 85 is pin-connectedby m ans of'a link 88 at itsupper end to the aforedescribed link member.80. The lower end of yoke 85embraces an operating rod'memb'er 90. 7

The operating rod '90 has threaded connection at 91 to the'saddle 30 andextends rearwardly therefrom through suitable supports or brackets 92 onthe frame 54 where it is slidably supported at its rear end wthin themandrel rod clamping head or bracket 56'. The rod 90 is embracedvby adownwardly extending 7 leg" of the afore-mc'ntioned bell crank 58 andcollars 100,102, and

The working faces of, the swaging elements 46 are formed with taperedgrooves 41 which are relieved at 49 out of contact with the bloom 48before and after its reduction. The forward or working stroke of thesaddle 30 carries "with it the oscillatable swagers 46 forwardly or'ftowards the right from their position viewed in Fig. 5, and causes theirgrooved'workin'g faces 41 to squeeze and roll an increment of the bloom48 down the tapered mandrel nose 60 into seized gripping relationshitherewith during a rear-re tion and forward elongation of the bloom*4'8. When the saddle '39 and swagers 4'6 approach their most forwardlyposition, at which period of travel the swagers are again out of contactwith the bloom, the collar 'lllo seoured on the "rod '90 engages thevdou'rnwardly 'depe'ni'ii-ng le'gof the bell crank 68 to oscillate thesame and its inter- 7 connected crank or indexing head 58, mandrel rodand-its attached tapered nose "60,fto= gether with its seized tubularbloom 48, through some angle such as 30. 'In the event the'indexing headis clamped on the bloom E8, the inde'k ing will be performed in the samemanner'as de scribed for the mandrelrod 5'5. The saddle '39 isthereafter reciprocated rearwardly to the left causing the groovedworking faces of the swaging elements 46 to roll back up the taperedreduced bloom 38 to smooth the same and elimi I04, I08 are adjustablymounted and secured on v the rod 90 on either side of its passagethrough the bell crank E8 and yoke member 05, the pur pose of which willbe hereinafter described.

In the present embodiment of the invention a tubular bloom, serving asthe material from which the exterior cable sheathing is fabricated, isintermittently reduced in increments of. its length and is sunk ontothecable' to be sheathed nate any that ma have exuded between the aworking grooves: 41.

The return or-smoothing stroke or saddle 39 and swagers 46 also servesto disengage the re duced portion or bloom 48 from the mandrel no e 60,and towards the end or the return stroke, during which periodtheswaggers are"out of contaotwith the'fbloo'm, collar' "I06 strikes thedepending arm of'yoke '85 to pivot the same aboutiits pivots 06 inaclockwise direction. In Iitial movement of the yoke '85 in the directionstated causes the eccentric cam link 00 to pivot clockwise and force theupper chuck I 4 down wardly to positively clamp the bloom '48 betweenchucks .14 and 15. The remaining rearward or right to left movement ofthe saddle 39 adva'nces the s'lidable housing 13 and itsclampedtube'bloom '40 a small increment of the bloom length to the right intothe position illustrated in Fig. 5, which places the saddle 39 andswagers 46 in position for a subsequent bloom reducin and elongatingoperation.

The collar I02 secured on the rod 90, on abut ment against thedependingleg of the bell crank position on the non-working (right toleft) stroke of the saddle 39. Also, the collar I04, on abutment againstthe depending leg of yoke 85, returns the yoke and its interconnectedelements, including the slide member I3 and its supported chucks I4 andI5, on the forward or working stroke of the saddle 39 at any intervalfollowing engagement of the bloom 48 by the swagers 46. Compressionsprings '(not shown) may be provided around aligning pins II whichproject into the chucks I4 and I5. Such springs would insure separationof the chucks I4 and I5 into non-clamping relationship with respect tothe bloom 48 following disengagement of the eccentric cam link 80 withthe upper chuck I4 following the advance or forward movement of thesaddle 39. In this same connection, compression springs (not shown) maybe installed on the operating rod 90, between the depending leg of crank68 and its cooperating collars I00 and I02, as well as between thedepending leg of yoke 85 and its cooperating collars I04 and I06.

It will be seen thus far that the bloom reducer 36 performs anintermittent bloom reducing operation. In the practice of the invention,employing the equipment of Figs. 4 through 10, the bloom 48 is chargedinto the bloom reducer mechanism which is then set in operation toprovide a relatively short length of reduced bloom. The mechanism isthen interrupted to permit threading a cable I08 through the hollowmandrel rod 55 and mandrel nose 60 where positive connection orattachment of the forward end of the cable is made with the bloom 48 atits reduced end. The bloom reducer 36 is again operated to produce asuflicient length of reduced bloom to permit pointing the same andthreading it through the sinking dies 3'! for positive attachment to thepower driven bull block 38. As in the previously described mechanism ofthe invention (Figs. 1 through 3) there is no appreciable relative axialmovement between the interior cable and its exterior sheathing memberduring the final sinking operation by-the sinking die nearest the drum38. There may however be a slight elongation of the exterior portion ofthe reduced tubular sheathing, as distinguished from the zone defined bythe internal surface brought into clamping relationship with theinternal cable I08, in the final sinking die.

Otherwise, the practice of the invention described in its associationwith the equipment of Figs. 4 through 10 is distinguished from thefirstdescribed practice only in that it incorporates intermittent bloom'reduction coupled with rotational indexing of the bloom between thereduction cycles. The rotational indexing'of the bloom should neverexceed 360 and may include angular step indexing up to 360 in totalangular displacement of the bloom. In any event the bloom should bereturned to its initial position after any single or series of indexingsteps not exceeding 360 to insure against twisting and/or kinking of theinterior cable.

It should also be observed, in view of theintermittent operation of thereducer mechanism 36, that a surplus or slack of reduced bloom andinterior cable must be provided between the reducer 36 and sinking die3'I.' This surplus is essential to permit uninterrupted or continuousoperation of the power-driven bull block 38, to perform the sinkingoperation on the cable, with out developing detrimental tensile forceson the cable, insulation or relatively thin-walled sheath ing material.

.8 It will be appreciated that alternative forms of mechanism have beenillustrated as means for carrying out the invention. The invention isnot to be limited to the specific forms of apparatus illustrated anddescribed herein since any tandem mechanism that will reduce arelatively thick-walled bloom and subsequently supply the same to asinking mechanism will function in a satisfactory manner to permit thepractice of the invention. It is significant, however, that the bloomreducing and sinking operations be so performed and coordinated thatrelative rotational movement in excess of 360 between the cablesheathing and cable be eliminated at all times, and that appreciablerelative axial movement between the cable sheathing and cable be avoidedduring the final sinking operation.

Commercial 16-pair paper-insulated telephone cable has been successfullysheathed with aluminum of 99.6% purity in accordance with the inventionhereinabove described by employin 44- foot lengths of aluminum bloom, 1inch outside diameterx 0.285 inch wall, each bloom having been reducedto inch outside diameter 0.049 inch wall and subsequently sunk onto thecable to provide minimum 500 lengthcoils of aluminum-sheathed telephonecable having an outside diameter of 0.455 inch and sheathing wallthickness of 0.050 inch. Sheathing bloom wall reductions up to 98 percent, and preferably within the range to 98 per cent, followed by one ormore sinking operations, have been tested and proved satisfactory in thepractice of the invention. It will be understood that the cold workreducing and sinking steps herein contemplated, when accompanied withthe loosely supported interior cable ,to be sheathed, overcome thedifficulties attendant the threading of cable through long lengths oftubing and following such a procedure with a single sinking operation.

Having described the invention and its mode of operation in associationwith alternative forms of apparatus, it is to be understood that theinvention is not limited to the exact description herein given butshould be interpreted in as broad a manner as is permitted by the priorart in the followin appended claims.

What is claimed is:

1. Apparatus for sheathing a continuous length of cable by utilizing arelatively short tubular bloom from which the sheathing is to befabricated, comprising cable supplying means, bloom reducing means andsinking die means placed n tandem, said bloom reducing means comprismg abloom reducing and elongating die mounted therein and capable ofreducing the bloom up to 98 percent, a hollow mandrel upon which thebloom is supported for reduction and elongation by the die and throughwhich the cable is fed from the cable supplying means, means foradvancing the bloom axially along said hollow mandrel into position tobe reduced and elongated by the reducin die, said mandrel being of afinal size, large than said cable to maintain a clearance relationshipbetween the cable and the bloom during the bloom reducing and elongatingoperation to allow. relative movement between the cable and bloom untilthe subsequent die sinking operation, said sinking die means comprisinga die member mounted in proximity to the bloom reducing means forsinking said reduced and elongated bloom into sheathing contact withsaid cable with a minimum of relative movement therebetween, andsheathed cable take up means for pulling said cable from said supplymeans through said hollow-mandrel and con-' jointly with said reducedand elongated bloom through said sinking die means. I

2. Apparatus for sheathing a continuous length of cable by utilizing arelatively short tubular bloom from which the sheathin 'is to befabricated, comprising cable supplying means, bloom reducing means andsinking die means placed in tandem, said bloom reducing means comprisinga bloom reducing and elongating die mounted therein, a hollow mandrelupon which the bloom is supported for reduction and elongation by thedie and through which the cable is fed from the cable supplying means,means for advancing the bloom axially along said hollow mandrel intoposition to be reduced and elongated by the reducing die, said mandrelbeing of a final size, larger than said cable to maintain a clearancerelationship between the cable and the bloom during the bloom reducingand elongating operation to allow relative movement between the cableand bloom until the subsequent die sinking operation, said sinking diemeans comprising a die member mounted in proximity to the bloom reducingmeans for sinking said reduced and elongated bloom into sheathingcontact with said cable with a minimum of relative movementtherebetween,and sheathed cable 'take up means for pulling said cable from saidsupply means through said hollow mandre1 and conjointly with saidreduced and elongated bloom through said sinking die means.

JOSEPH E. MCLAUGHLIN.

